Because it can be socially embarrassing and isn't life-threatening, many people suffer with their incontinence because they don't talk about the condition with their physicians. Despite the secretiveness surrounding it, incontinence is anything but rare. Experts estimate that 35 to 50 million Americans, including children, have periods of occasional or frequent involuntary urine loss. Because of the anatomic differences and the effects of childbirth on the pelvic muscles, women experience incontinence 2 times more often than men. The number of women undergoing surgery for incontinence in the United States since 1979 has doubled.
Incontinence occurs more frequently as people get older, but it is not caused solely by aging. It results from weakening of the pelvic muscles because of childbirth, obesity, or aging (which can also reduce the size of the bladder), as well as a variety of urinary conditions, such as:
- Enlarged prostate(benign prostate hyperplasia);
- Urinary tract infections; and
- Pelvic floor dysfunction.
In a normally functioning bladder, the bladder fills to capacity after receiving typically about 8 to 16 ounces (1 to 2 cups) of urine from the kidneys. The stretch-sensitive nerves in the detrusor muscle, which makes up the bladder, then sends a signal to the spinal cord and brain, triggering an urge to urinate. Two ring-like muscular valves, an internal sphincter in the bladder neck and the external sphincter at the external outlet of the urethra, normally are closed to hold in urine flow. The internal urethral sphincter begins to relax only when the spinal cord receives the nerve signal that the bladder is full. Yet it is the brain that has final say, holding the external sphincter shut until a person can find a place to go the bathroom.
Incontinence can take several forms: stress, urge, reflex, overflow, and functional.